1. Field of the Invention
The present invention relates to a container with an easily attachable/detachable lid (referred to as "easily attachable/detachable lid mounted container" in the specification and claims) in which a lid can be easily attached on and detached from a container body. More specifically, the present invention relates to an easily attachable/detachable lid mounted container which is preferably used as a container for housing, storing and transporting thin-plates, such as semiconductor wafers, storage disks, liquid crystal glass substrates and the like.
2. Description of the Related Art
As a conventional easily attachable/detachable lid mounted container, a container disclosed in the Japanese utility model publication No. Hei 6-13114 (No. 13114/1994) entitled "Engagement Mechanism for Sealed Container" is known.
As shown in FIGS. 2 through 4, the sealed container 51 includes generally a container body 52, and a lid 53 for closing the top opening of the container body 52. Each of the two opposed side walls of the lid 53 is provided with an engagement piece 54 which extends downward. The engagement piece 54 has an operation opening 55 formed at the center thereof, and engagement holes 56 formed on the both sides of the operation opening 55. The container body 52 is provided with an engagement member 57 which engages with the engagement hole 56 of the engagement piece 54. The engagement member 57 has an inclined surface 57A which abutting contacts with the engagement piece 54 so as to press the engagement piece 54 outwardly.
In the conventional sealed container having the above configuration, when the lid 53 is placed on the container body 52 and pressed downward from above, the engagement piece 54 slides down along the inclined surface 57A and is thereby spread, whereby the engage member 57 engages with the engagement hole 56. Thereby, the lid 53 is attached on the container body 52 and reliably secured thereon.
When the lid 53 is removed from the container body 52, the engagement pieces 54 are bent. Specifically, the operator seizes, with his hand, the operation opening 55 of each of the engagement pieces 54 and bends the engagement pieces 54 away from each other (i.e. toward the right in FIG. 4), so as to release the engagement hole 56 of the engagement piece 54 from the engagement member 57. Thereafter, the lid 53 is removed from the container body 52.
As described above, when the operator intends to remove the lid 53 from the container body 52, he needs to bend the two engagement pieces 54 away from each other, and to release the engagement holes 56 of the pieces 54 from associated engagement members 57.
However, when the operator lifts the lid 53 upward while bending the engagement pieces 54 away from each other, he must perform the operation of pulling the engagement pieces 54 away from each other, and concurrently the operation of lifting the lid 53 upward. Thus, the conventional container has a poor usability so that work efficiency is very low. Under the circumstances, if the operator removes lids from a small number of containers, he does not have difficulty in removing them. However, if he must remove lids from a large number of containers, he has difficulty in the removing operation because the poor usability of the container imposes a heavy burden on him.